I suspect we are having similar problems. The side that ends up sagging a bit is farthest from where you turn for advancing the quilt. Goes great for the first time, just a bit of slack the second time and progressively gets worse. When advancing the quilt, I roll it from the opposite end of the crank. The reason this is happening is because where ever you crank from will get the most torque and roll up much better. Sometimes I do go back and forth to crank especially if it is a large quilt, queen or king size. I will crank a couple times on one end, go to the other and do the same. This is not a problem with just the HQ, any system can have this problem. It is strictly a matter of physics.

Hmmmmm......Eparys, your suggestion about adding the smaller pieces of batting is interesting. I would have never thought of that. And Paper Princess, I am on a mission now to measure the distance between bars. I'm a little confused in your description of "moving the machne". Are you saying that the machine may be adding weight and thereby changing the distance between the bars? Since the machine doesn't actually sit on the bar, how does that help. I appreciate the input thus far and will report back with results. Thanks again to all !!!

I don't think the machine adds weight to the bar. It seems that if the machine head is over the quilt, the bed of the machine causes a slight drag on the back of the quilt so that end rolls tighter which results in an uneven roll. I get much better results if I move the machine way to the side off the quilt. I do mostly throws, so I have usually have enough room to do this. With wider quilts, I just roll and measure & adjust as needed.

I find that I have trouble like this if the batting does not extend all the way to the edges of the backing. This seems to make the backing roll a bit crooked onto the takeup roller. If I have this situation, I just make sure I check on each roll, and give the "loose" side a bit of a tug to ensure it has advanced the same distance as the rest of the (thicker) quilt body.